In general, a bearing for large rotating shaft machines comprises a base ring which is an annular structure designed to be assembled around a rotating shaft. Bearings may be designed as a journal bearing for providing a co-axial support surface for the rotating shaft or it may be a thrust bearing for providing a radial support surface for the rotating shaft in case of shaft thrusts in the axial direction. There are also combined journal and thrust bearings which is the subject of the present discussion. Further, lubricant may be required at the bearing surfaces at different flow and pressure conditions to account for the particular bearing surface being lubricated and for the particular operating condition for the bearing as a whole. The improved bearing lubrication device provides for the required flow conditions while allowing a standardized bearing assembly.
In combined journal and thrust bearings of the prior art the control of lubrication fluid, e.g.; oil, to the bearing as a whole was maintained by a plurality of screwed in orifice plugs threaded into the base ring. Several orifice plugs were positioned around the periphery of the base ring (one per journal pad). The oil flow to each journal pad was controlled by a radial orifice hole drilled into the base ring. The oil flow to the thrust bearing surfaces was controlled by orifice holes machined into opposite ends of the base ring. The size of each orifice hole was changed on each application due to changes in oil flow requirements dictated by design conditions.